A medic puts a sign on a house after people inside received anti-cholera vaccines in Sanaa, Yemen, on April 24, 2019. Yemeni Health Ministry in collaboration with WHO and UNICEF launched a 6-day home-to-home emergency immunization campaign against cholera in three most seriously affected districts in Sanaa with an aim to target all people from age of one year and above except pregnant women. (Xinhua/Mohammed Mohammed)